Samuel i



(No Model.)

S. I. SCOTT.

DENTAL ENGlNE HAND PIECE. No. 395,252. Patented Deo. 25, 1888.l

UNITED STATES PATENT OEETCE.

SAMUEL I. SCOTT, Ol.i1 VASIIINGTON, DISTRICT OF COLUMBIA.

SPECIFICATION forming part of Letters Patent No. 395,252, dated December 25, 1888.

Application filed March 31, 1888i Se1'ialN0.269,207. (No model) vTo all whom, may concern:

'which the tool may be inserted in the chuck,

withdrawn therefrom, and replaced without interrupting or stopping the niotion of the machine. The clamping or unclainliiing ot' the tool may be cl'teetcd by the thunib or linger olf the hand while the hand-piece is held therein, thus Ieavingthe other hand free to handle the tool.

A further object consists in the construetion and arrangement oll certain details, hereinafter described.

I accomplish these objects by the ineehanism illustrated in the accompanying drawings, in which- Ifigurel is a longitudinal section through the center ol the hand-piece.` Figs. 2, 2S, and -l are inodilied lforins ort' the chuck. Fig. 5 is a side elevation of the Vrear adjustable bearing. Fig. l is a transverse section ol the hand-piece, showing the yoke-lever t'or opere ating the clamping mechanism. Fig-. T isa detail showing the bolt and sleeve, and Fig. Sis a detail of another li'orni of rhuck.

A represents the outside case, and I3 the spindle or (lriving-shaft, which is bored ont, as shown at l). The front end screwthreaded, as shown at o', and on this part is threaded a tubular cap, Il?, having a contracted The parts B and Il? together forni ahollow driving-shaft, having front and rear bearings, b and lr, The front end of the bored-out shaft is beveled outwardly, as shown at b, and within the hollow shal't is placed a bolt, C, having a conoidal or wedge-shaped point, c.

The hollow shaft B is provided with small slots ZF, and through these slots and through the bolt C are passed two rivets, c c', which are secured in collars es bg. Intermediate between the two collars bs b3 is secured a loose sleeve, I), havingA a groove, d, therein. This sleeve is loose upon the hollow shaft B, but is prevented from revolving therewith by a cross-bar, n, which engages one of the pins from the lever-yoke The lever-yoke E is composed of two parts, e e, pivoted upon a lug, a, projecting from the outside case, A, and in the parts e of this yoke are screw-threaded pins e?, the ends of which project through slots a2 in the outer case, A, and engage the gromrey d in the sleeve l). The `Yoke surrounds the outer case and projects a slight distance above the saine, and pressure on the upper end of the Lvoke by the thinnb or iinger causes a movement of the bolt C back and forth within the hollow shaft. The yokepieces e are provided with hinges e3 and a By loosening` the clamp e* the 1 case, thus allowing the instrument to be taken apart without first taking olf the `voke. j stead of this lever or yoke, I may use a pin or screw with a knob on its outer end.

F is the chuck. Ijn'efertoniake this chuck l? hollow throughout and slotting out the front end, so as to forni two or incre jaws, f2, which are adapted to clamp and surround the tool. The rear end of the chuck is also slotted out to forni two or more arms, f3, which abutagainst the inclined surface o6 of the hollow shaft I3. The central portion, f, of the chuck I prefer io make thicker than the arms and jaws, and through this thickened portion or belt I inserta pin, f. The tool being flattened, as shown in the drawings, lits against the pin, and is thereby prevented from turnbe seen that this bearing receives the thrust of the shaft, which niay be caused by using the tools. In order to prevent this bearing IOO from becoming' loose in the outer case, I use va jam-nut, H, which is screwed upon the bearing until it rests against the milled surface. The bearing is then screwed into the outer case until it rests against the shoulder X of the shaft B. The jam-nut is then screwed down hard against the end of the case. As a further security to the joint, the bearing-block G is provided with a series of holes, g2. These holes are tapped to receive a set-screw, g3. A recess is formed partly in the j am-nut and partlyin-the end of the case, through which the screw passes. A portion of the set-screw where it passes through between the jam-nut and the end of the case is cut away on one side, so that in giving the screw a half-turn it presents a fiat side to the end of the case, which may then be unscrewed; but when turned to occupy both parts of the recess the joint is securely locked. The head of the screw g3 may be marked to indicate the fiat side. A very fine adjustment may thus be obtained. The screw-threaded part of the bearing G being' forty threads to the inch, an d ten holes being provided, gives an adjustment Of one four-hundredths 0f an inch. The connections between the driving-shaft B and the motive power are as commonly made and need nodescription here. v

The chuck has springjaws of the usual kind, and they are brought down upon the' tool by being forced into the contracted mouth of the tubular cap which forms a part of the hollow shaft, as hereinbefore explained. The forcing forward of the chuck is effected by the sliding bolt having a conical or wedgeshaped surface which en gages with the springarms of the chuck.

In the modification shown in Fig. S the sliding bolt is provided with a hollow end, within which the end of the tool I is secured. The end of the bolt, however, is provided with a conical or wedge-shaped surface, which engages the arms of the chuck in the same manner as explained with reference to Fig. vl.

In the modification shown i'n Fig. fl the tubular cap b2 is slotted and the arms of the chuck are provided with wedge-shaped projections which fit into the slots and operate in the same manner to force forward the chuck as described with reference to the inclined surfaces shown in Fig. l.

An important feature of my invention consists in making an abutment on some part of the driving-shaft, as before explained, upon which the rear end of the chuck or some part directly connected therewith rests, and in making one or both of the abutting surfaces inclined ,to the axis of the shaft, so that a thrust in or out of one of the parts will cause the proper movement of the chuck.

It will be seen that by my construction I make u se of the wedge orinclined plane both in the abutting surfaces and the end of the sliding bolt which forces outward the arms of the chuck. It will also be seen that in the use of the tool when pressure is applied to the end thereof these wed ge-shaped surfaces tend to bind the chuck morefirmly to the tool and to the hollow driving-shaft, so that the harder the tool is pressed the more secure will it becoine. Another point to be considered in this connection is that the operating' lever or button projects to the outside of the case and receives the hand-pressure when the tool is used, thus tending to move the sliding bolt forward and still further tighten the chuck upon the tool. On t-he hollow shaft back of the `rear collar D8 is located a spiral spring, Ii, which rests on the collar X of the shaft.

This spring tends to keep the sliding bolt in the forward position. rlhis spring might be located within the hollow shaft, instead of being on the outside, as shown in the drawings, or it may be dispensed with, as the closing of the chuck does not depend necessarily upon the action of the spring. pensed with, the bolt may be split, as at Y in Fig. 7, and spread so as tomake it bind with sufficient :friction in the hollow shaft to hold itin any desired position.` l

In Figs. 2, 3, and 4 I have shown a two-part chuck, one part being provided with springjaws to clamp the tool and the otherpartbeing provided with spring-arms to co-operate with the sliding bolt. K represents the part having the spring-jaws, and K the part having the spring-arms. The abutting ends k k are made solid and have plain surfaces abutting together. The friction between these abutting surfaces is sufficient when the chuck is clamped within the tubular case to make it operate as though made in one piece. In order to make the length of these chucks adjustable, I fit into the end of one of the parts a screw-plug, k2, as shown in the drawings.'

By screwing the plug in or out the length of i the chuck maybe regulated as desired.

Having thus described my invention, I claim and desire to secure by Letters Patent'of the United Statesl. In a dental hand-piece, the combination of an outer case, a hollow driving-shaft having a contracted mouth and a forward inclined abutting' surface, b, an independent chuck provided at its forward end with tool-receiving spring-jaws and having spring-arms at its rear end, a sliding' bolt for engaging and forcing the rear spring-arms ofthe chuck outward and against the adjacent abutting surface of the hollow driving-shaft, thereby forcing the chuck forward and causing its spring'- jaws to grip the tool, and a lever for actuating said bolt from the outside of the case, substantially as described.

2. In a dental hand-piece, the combination of a hollow driving-shaft provided with slots and having a forward inclined abutment and a contracted mouth, a sliding bolt having a wedge point, two collars adapted to slide on the shaft and connected to the sliding bolt by pins or rivets passed through the slots in said shaft, a loose non-rotating sleeve located 011 the shaft between said collars, a lever for If the spring is dis- A IOO IIO

actuatin said sleeve, whereby the sliding bolt can be moved back and forth, and a chuck having spring-arms to engage said bolt and spring-jaws to engage and hold the tool, substantially as described.

3. In a dental hand-peee, the combination of thehollow driving-shaft, the collars sliding thereon, the sliding bolt connected with said collar and provided with a wedge point, the loose sleeve and lever pivoted to the outer case and projecting' out from the same and engaging the loose sleeve, and the chuck having spring-arms to engage the bolt, substantially as described.

4c. In a dental hand-piece, the combination of a hollow driving-shaft having an inclined abutting surface, l1, a tool having a liattened inn er end, a slidin g bolt havin a wedge point, and a chuck having' spring-arms which abut against the inclined surface b and engage the point of said bolt, spring-jaws which engage the tool, and a central re-enforced portion or belt, f, provided with a transverse pin, f', to l engage the flattened portion of the tool, substantially described.

5. In a dental hand-piece, the combination, with the outer case having' a lug thereon, ot' a yoke pivoted to said lug', encircling' said outer case, and adapted to engage .the loose sleeve on the dri ving-shaft, substantially as described.

6. In adental handpiece, the c'on'ibination, with the outer case having' a lug, of a yokelever pivoted to the lug, the arms of saidyoke being pivoted at e3 and held together at the top by a clamp, substantially as described.

'7. In a dental hand-piece, an outer ca-se screw-threaded at its en d, in combination with a bearing' having' a screwthreaded portion and provided with a series of holes, g2, a jamnut adapted to be screwed up against the end ot' the case, and a screw-pin adapted to t either of said holes and to pass through a recess between the jam-nut and the case, sub stantially as described.

8. In. a dental hand-piece, the combination of an outer case, a hollow driving-shaft having inclined abutting' surfaces, a sliding conically-pointed bolt working parallel therewith, a loose ring or collar connected with said bolt, and a lever connected with said collar and projecting through the outer case, whereby the bolt may be forced forward or backward while thc shaft is in motion, substantially as described.

9. In a denial hand-piece, the combination of an outer case, a hollow driving-sliai't, a chuck having spring-arms, and a conicallypointed bolt having its rear end split to itform spring-jaws to hold the bolt firmly in its forward position, substantially as described.

l0. In a dental hand-piece, the combination of an outer case, a slidin bolt, a chuck, ahollow shaft havin a rear bearing' provided with a wide shoulder, X, an ac'ljustable bearingblock, G, to engage said shoulder, and a jamnut, H, substantially as described.

1l. In a dental hand-piece, the combination of the outer case, a driving-shaft, a tubular bearing-block, G, having holes g2 at equal distances apart, a jam-nut screwing against the outer case, and a small tlat-sided screw, g3, passed through the jam-nut to engage one ot' said holes, whereby the bearing-block can be adjusted to a small fraction ot' an inch and be securely fastened to the case, substantially as described.

12. .In a dental hand-piece, the combination of. an outer case, a driving-slmtt, a two-part chuck having' a length-adjusting screw, and a chuckactuating bolt, substantially as described.

In testimony whereoi' I altix my signature in presence ot two witnesses.

GEO. H. KENNEDY, J. E. KENNEDY. 

